Classifications

• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B14/00—Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
  • C04B14/38—Fibrous materials; Whiskers
  • C04B14/48—Metal
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B14/00—Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
  • C04B14/02—Granular materials, e.g. microballoons
  • C04B14/34—Metals, e.g. ferro-silicon

Definitions

• the present invention relates to the formation of concrete tunnel linings and, more particularly, the casting in situ of concrete within a tunnel.
• tunnels subterranean structures
• One of the techniques used for this purpose is to pump concrete between a metal shell as it is advanced along the subterranean structure, the concrete filling the space between this shell and the rock or earth wall.
• the concrete thus remains in place as a timbering while the tunnel is advanced in the desired direction, e.g. by tunnel excavating machines.
• the present invention relates to improvements in such systems and, in general, to the provision of a reinforced concrete for the specific purpose of lining tunnel walls by pumped emplacement.
• a tunnel wall which is lined with concrete is generally more stable than a wall built up or timbered from other structural elements and is highly desirable for the formation of water-carrying tunnels, tunnels for transport purposes or mine-shaft tunnels and the like.
• the concrete structure within a tunnel must be capable of withstanding compressive forces which result from sinking of the earth, hydrostatic pressures and the like.
• the tunnel lining does not have the desired degree of homogeneity or the isotropic characteristics which have been found to be necessary to resist the stresses to which the lining may be subject.
• the concrete composition of the present invention has been found to be readily pumpable so that it can be forced between the support shell and the tunnel wall and has both the tensile strength characteristics and the compressive strength characteristics of reinforced concrete without the danger of separation and balling up of the filling material.
• the tunnel linings produced by the concrete composition of the present invention are thus homogeneous and isotropic with respect to their properties over large tunnel stretches.
• the concrete composition of the invention consists essentially of a concrete of group II (BII) of German Industrial Standard DIN 1045 which corresponds essentially to type II concrete of the Federal Specification SS-C-192 for portland cement.
• Such a concrete can have a cement content of 400 kg/m 3 with a slump (DIN 1045) of say 52 cm in its pumpable state.
• the aggregate composition should lie in the sieve-size range between lines A and B of the curve (FIG. 4) at page 221 of the so-called Betonkalender 1978 (concrete calendar 1978) containing an extract of German Industrial Standard DIN 1045.
• the maximum aggregate size is 16 mm.
• this concrete is combined with a steel-pin additive which consists of about 100 kg/m 3 of concrete of steel pins (the preferred additive range being between 50 and 150 kg/m 3 of concrete), the steel pins having a length between about 35 and 50 mm, preferably between 40 and 45 mm, and a diameter between 0.8 and about 1.2 mm, preferably about 1 mm.
• a steel-pin additive which consists of about 100 kg/m 3 of concrete of steel pins (the preferred additive range being between 50 and 150 kg/m 3 of concrete), the steel pins having a length between about 35 and 50 mm, preferably between 40 and 45 mm, and a diameter between 0.8 and about 1.2 mm, preferably about 1 mm.
• This concrete is mixed with water and is pumped into the space between a support shell and the tunnel wall.
• the additive consisting of steel pins of a diameter of 1 mm and a length of 40 to 45 mm.
• the pins can be of circular cross section or can be somewhat flattened in which case the maximum thickness dimension is about 1 mm.
• the steel pins can be admixed with the gravel-cement premix without special techniques and the concrete structure is found to be formed without separation or singular points or zones of the type characterizing earlier systems.
• Another surprising advantage of the concrete composition and method of the present invention is that it provides a significant improvement in the tensile strength and the compressive strength of the concrete over earlier tunnel-lining systems.
• a particularly important advantage is the increased earlier setting strength with the steel-pin additive, thereby facilitating the speed with which the concrete sets to a high compressive strength and the rate at which tunnel structures can be made.
• the aggregate can be sand and gravel with a continuous particle-size distribution up to 32 mm and including aggregate from at least three particle-size groups. It can also consist of a noncontinuous distribution from at least two particle-size groups which are separately prepared, stored and combined.
• One particle-size group must lie in the range of up to 2 mm. For aggregate up to 8 mm and up to 16 mm, it suffices to separate the aggregate into one group up to 2 mm particle size and a larger particle-size aggregate group. Dust particulates are not considered as a particle-size group in accordance with this invention.
• the water-cement ratio (W/C ratio), i.e. the ratio of the water content W to the weight of cement C in the concrete, need not be particularly great in accordance with the present invention. It suffices to use a water-cement ratio which will bring about the desired consistency and viscosity to enable the concrete to be pumpable.
• the water-cement ratio can thus be up to 0.75 and where the cement is of strength class 250 the value should not exceed 0.65.
• the concrete which is used should be from strength classes Bn50 to Bn550, the dimensions of the Bn numbers being in kilopond/cm 2 (i.e. kilograms force/cm 2 ).

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Ceramic Engineering (AREA)
• Civil Engineering (AREA)
• Materials Engineering (AREA)
• Structural Engineering (AREA)
• Organic Chemistry (AREA)
• Lining And Supports For Tunnels (AREA)
• Excavating Of Shafts Or Tunnels (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)

Applications Claiming Priority (2)

Related Child Applications (1)

Publications (1)

Family

ID=6017956

Family Applications (2)

Family Applications After (1)

Country Status (3)

Cited By (5)

Families Citing this family (6)

Citations (6)

Family Cites Families (1)

• 1977
  • 1977-09-02 DE DE2739568A patent/DE2739568C2/de not_active Expired
• 1978
  • 1978-08-08 AT AT576678A patent/AT360576B/de active
  • 1978-08-30 US US05/937,971 patent/US4209338A/en not_active Expired - Lifetime
• 1979
  • 1979-05-21 US US06/041,110 patent/US4264542A/en not_active Expired - Lifetime

Patent Citations (6)

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